Emissions of Volatile Organic Compounds (VOCs) from Manufacturing Process in a Plywood Mill

Volatile organic compounds (VOCs) from polypropylene (PP) seriously restricts the application of PP in an automotive field. Herein, the traceability of VOCs from PP resins during manufacturing process and accelerated photoaging degradation was clarified on basis of an accurate characterization method of key VOCs. The influence of PP structures on changing the accelerated photoaging degradation on the VOCs was systematic. The VOCs were identified by means of Gas chromatography (GC) coupled with both a hydrogen flame ion detector (FID) and a mass spectrometry detector (MSD). Results showed that both the molecular structure of PP and the manufacturing process affected the species and contents of VOCs. In addition, the photoaging degradation of PP resulted in a large number of new emerged volatile carbonyl compounds. Our work proposed a possible VOC formation mechanism during the manufacturing and photoaging process. VOCs from PP resins were originated from oligomers and chain random scission during thermomechanical degradation. However, β scission of alkoxy radical and Norrish tape I reactions of ketones via intermediate transition were probably the main VOCs formation routes towards PP during photoaging degradation. This work could provide scientific knowledge on both the accurate traceability of VOCs emissions and new technology for development of low-VOCs PP composites for vehicle.

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Investigation of Volatile Organic Compounds from the Manufacturing Process of Recycled PET Fibers Using TGA-DTA/MS Technique

Materials Science Forum ◽

10.4028/www.scientific.net/msf.944.1221 ◽

2019 ◽

Vol 944 ◽

pp. 1221-1225

Author(s):

Ji Yue Hu ◽

Ye Chen ◽

Shan Shan Liu ◽

Fu You Ke ◽

Ling Ling Gao ◽

...

Keyword(s):

High Temperature ◽

Volatile Organic Compounds ◽

Thermal Degradation ◽

Thermal Oxidation ◽

Organic Compounds ◽

Manufacturing Process ◽

Melt Spinning ◽

Recycling Process ◽

Volatile Organic ◽

Pet Fibers

Recycling is promising to dispose the wasted Poly (ethylene terephthalate) (PET) fibers currently. However, high temperature and oxygen in the recycling process may accelerate the degradation of PET and residual dyes, resulting in the volatile organic compounds (VOCs) emissions, which will do serious harm to the environment and human health. Exploring the source of VOCs is significant to remove VOCs and keep products safety. This study was carried out to investigate the influence of high temperature on the release of four VOCs (formaldehyde (CH2O), acetaldehyde (C2H4O), benzene (C6H6) and toluene (C7H8)) during the recycling process of PET fibers, utilizing thermogravimetric analysis and differential thermal analysis coupled with mass spectrometric (TGA-DTA/MS). The atmospheres and heating conditions of esterification, polycondensation and melt spinning were simulated by TGA with various atmospheres and programmed heating processes (heating from 50 °C to 240 °C in Ar, 280 °C in Ar and 280 °C in air, respectively, and then maintaining for 30min). Bis (2-hydroxyethyl) terephthalate (BHET) (esterification product) and virgin PET (VPET) were used to explore the thermal degradation of PET. White PET popcorn, black PET popcorn and dyes were used to explore the effect of dyes on the release of VOCs. The results indicated that: (1) Aldehydes including formaldehyde and acetaldehyde are generated during the manufacturing process of PET, mainly due to its thermal oxidation;(2) Aromatic compounds including benzene and toluene are originated from the disperse dyes. So the degree of dye removing has a great influence on the production safety; (3) Thermal oxidation causes more VOCs than nonoxidative thermal degradation. So in the stages of melt spinning and slightly alcoholysis, usually in O2 containing atmosphere, devolatilization should be developed further.

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Volatile organic compounds throughout the manufacturing process of Mozzarella di Gioia del Colle PDO cheese

Czech Journal of Food Sciences ◽

10.17221/129/2020-cjfs ◽

2020 ◽

Vol 38 (No. 4) ◽

pp. 215-222 ◽

Cited By ~ 1

Author(s):

Giuseppe Natrella ◽

Giuseppe Gambacorta ◽

Michele Faccia

Keyword(s):

Acetic Acid ◽

Discriminant Analysis ◽

Volatile Organic Compounds ◽

Organic Compounds ◽

Manufacturing Process ◽

Hexanoic Acid ◽

Oxidation Reactions ◽

Total Volatile ◽

Complex Profile ◽

Volatile Organic

The evolution of volatile organic compounds during the production process of Mozzarella di Gioia del Colle (traditional type) was investigated in comparison with citric mozzarella (industrial type). The total volatile concentration in the traditional curd was ten times higher than milk, versus only twice as much in the industrial type. In both technologies, the concentrations decreased from curd to mozzarella at the same rate, due to losses during the stretching phase. The higher microbial activity in the traditional product was responsible for a much more complex profile, characterised by 2- and 3-methylbutanal, acetoin, ethanol, 3-methyl-1-butanol, acetic acid and ethyl-acetate. In contrast, the industrial mozzarella had a very simple profile, with the most important compounds being directly derived from the milk, the oxidation reactions, or the activity of the adventitious microflora such as acetone, hexanal, nonanal, and hexanoic acid. According to the discriminant analysis, Mozzarella di Gioia del Colle had a very different profile than the milk used, whereas the industrial mozzarella was more similar to the milk.

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